S200 power tuning and adjustment

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Paddy1000111
Posts: 7
Joined: Tue Jun 16, 2020 12:54 pm

S200 power tuning and adjustment

Mon Jul 20, 2020 8:24 am

Hi Everyone,

Before we start I know this is a "dodgy topic" and I am aware of all the laws etc.

Anyway, down to business. My S200 is coming up on 15 years old now and the cylinder is leaking (around 30 bar a day loss) and I think the little aluminium tube on the inside on the outlet valve has come loose as it rattles like mad if I shake it. (I know I should have checked the cylinder before but I've always used regulated, clean, diving air). Long story short I am going to be stripping it down to nut and bolt and rebuilding it, taking the opportunity to sort out any small scratches and install a Lane pressure gauge. I was going to put a regulator on but hes on holiday now so I will sort it out at a later date.

After I have rebuilt I want to "retune" it. Is there a tuning guide anywhere? Going back a few years it started firing way under power and I took the hammer spring out to find a piece of swarf in there. since re-assembling and tuning back down below 12ft/lb its never been right, It seems to guzzle air. Hence the need to re-tune.

Am I best to re-set the outlet valve after the seal change to the original screw depth or is there a "spring weight" that's best? I noticed with the regulators the spring weight is what get's set?

Can I set the "power screw" to flush with the inside of the choke, effectively meaning it's not doing anything then set the power on the firing spring or has the firing spring, outlet valve and power adjustment screw got to be balanced?

For reference, it's a .177.

Thanks!

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Paddy1000111
Posts: 7
Joined: Tue Jun 16, 2020 12:54 pm

Re: S200 power tuning and adjustment

Tue Jul 21, 2020 8:52 am

Just a quick update! Spent the whole day doing the rebuild. Fixed a lot of small issues, polished the bolt, reset the trigger etc. The small aluminium tube on the outlet valve was loose and not really attached... I'm now in the market for an external regulator for it, HUMA is out of stock, Lane is away. Does anyone know where I can get an external regulator asap?

Thanks!

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Raj
Posts: 1965
Joined: Sun Feb 15, 2015 9:36 pm
Location: Rugby

Re: S200 power tuning and adjustment

Tue Jul 21, 2020 9:08 pm

Is there a tuning guide anywhere?
There used to be but not sure where right now. Depends on what you mean by tune. There are a number of refinements possible -
1. Trigger tune with upgrade to rounded heads on the sear screws
2. Floating the barrel
3. Polishing up the striker and main spring guide
4. Polishing up the cocking arm and associated linkages and pins
5. Polishing up the loading bolt shaft
6. Eliminating the play between the Firing Valve End Plug and the Breech Body

I can talk you through these. Pretty easy to work with the S200.

Am I best to re-set the outlet valve after the seal change to the original screw depth or is there a "spring weight" that's best? I noticed with the regulators the spring weight is what get's set? Yes ... there is an optimum setting for the valve spring loading depending on which regulator you go for. If not adding a regulator, then it is best to have the spring set as it was.

Can I set the "power screw" to flush with the inside of the choke, effectively meaning it's not doing anything then set the power on the firing spring or has the firing spring, outlet valve and power adjustment screw got to be balanced? Ultimately, it is all about balance. If regulating, then I found that -
1. Easing the venturi screw out all the way
2. Then setting the power slightly higher than you target but stay legal, set this at 11.8 foot pounds. Thus, nothing you do to the venturi will let it creep into illegal territory.
3. Then winding the venturi screw down slightly to get the desired number ... say 11.6 or 11.7 foot pounds ... to be the best way. You tend to get less flyers and odd high /low velocity if you do this.

Best to chat really.

Raj
“It's the Indian, not the arrow"

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Paddy1000111
Posts: 7
Joined: Tue Jun 16, 2020 12:54 pm

Re: S200 power tuning and adjustment

Sun Jul 26, 2020 11:12 pm

Thanks for the help Raj! I've gone for the Lane Mk9 external that I was able to source from Rat Works as Lane is away on holiday.

So Far I have:

Drilled the transfer and barrel to 3.5mm
Set the choke to flush and filed the end flat to reduce vortexes
Aligned the transfer port and the barrel
set the exhaust valve to 5.9kg
Rounded the heads on the sear screws and polished the heads
floated the barrel
Cleaned up the bolt and increased the size of the divot on the bolt for the locking ball bearing so the bolt locks down properly and put a high-end grease on it which makes it feel like double cream
installed a shim between the exhaust valve and the body to take out the play
Started to refinish the stock, it was looking rather worn and I'm also installing an adjustable butt and cheek piece.
And also lost the C-clip for the firing pin(?)... I've pinged Julian an email.

I've still got to clean/polish the cocking arms. I've ordered some 3mm 0.1mm washers for my trigger to as the trigger arm has 0.24mm play left to right so I thought I might be able to reduce that a little.

Could you expand on what you mean with the striker and main spring guide polishing for me?

I noticed in the Lane regulator manual it says about removing weight from the hammer. Would I gain anything from this? The hammer seems pretty light and small compared to, for example, an s400 hammer which is like a spring loaded 16oz ball peen.

Thanks!

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Raj
Posts: 1965
Joined: Sun Feb 15, 2015 9:36 pm
Location: Rugby

Re: S200 power tuning and adjustment

Wed Jul 29, 2020 7:25 pm

Wohoooo !!!! Well done, I say! 8-) :D

To respond to your questions ...

When the rifle is fired, the Striker (No.25) slides within a bore in the Breech Body (No.13). It is a smooth sliding fit and it may be worthwhile inspecting the outside diameter of the striker for any wear, score marks or manufacturing scars. If any, you can smooth off with a really fine grit wet and dry paper so that it moves consistently when fired. Same for the bore but as it is an aluminium alloy and also really hard to get to, I have left it alone after inspection.

Likewise, the Main Spring Guide (No.24) slides in the Main Spring. Worth checking that the spring hasnt marked it in any way or that it isnt wearing unevenly etc. Also, the forward face that makes contact with the Striker can be finished smooth with fine grit paper.

I liked the 'Double Cream' reference. It is how i would describe the bolt action on my S200s. :lol:

The Jesus Circlip (No.42) ... well, what can I say. I once found it snapped in two in my rifle and it was interfering with the trigger sears. I had heard horror stories about people struggling to get it back in, once it is removed - hence the name. I found a neat solution when i replaced mine. With the air cylinder off, I pushed the Striker Pin back by dropping a suitable sized steel ball on the pin and gently screwing the air cylinder back in while holding the Breech Body upside down and this seemed to make the groove visible. All you need then is a pair of long nosed pliers.

Image

Finally, a Rowan trigger upgrade made a massive difference too.
“It's the Indian, not the arrow"

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Paddy1000111
Posts: 7
Joined: Tue Jun 16, 2020 12:54 pm

Re: S200 power tuning and adjustment

Thu Jul 30, 2020 11:36 am

Thanks for the reply Raj! It's typical that I took it apart and reassembled it before deciding to drill the transfer. When I went to put it all back together, I put the striker pin back in with the cirlip and realised I needed it out to put a 3.5mm pin up through the transfer port to do the barrel and transfer port venturi screw alignment so took it out for the second time. I left it clamped in the needle nose pliers whilst I installed the barrel and screw. The pin was then tight in the port so what did I do, I took the pliers to pull it out and then realised I had the c-clip in there :oops: Anyway, an hour, a torch and an 8 inch magnet couldn't find it so I gave up looking!

I've since polished the striker as it wasn't perfect and taken the very slight rounded corner off the sear so it's nice and sharp again. (I've put a lot of pellets through this gun). The port in the block wasn't worth messing with. It wasn't rough.
I've also polished the faces on the spring, polished the spring guide face and spring bearing surface. I've got everything prepared to go back together with some shimano bantam fishing reel oil as it's super thin.

I already have the old style, non adjustable brass trigger from rowan. I want a trigger similar to the hft500, i.e. One that has a rounded end a bit like a pistol bullet as I feel it will give me more feel. No idea where I would get one though!

I'll get some pictures up when it's all done. The stock looks fantastic now!

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Raj
Posts: 1965
Joined: Sun Feb 15, 2015 9:36 pm
Location: Rugby

Re: S200 power tuning and adjustment

Thu Jul 30, 2020 8:26 pm

Great work!

I know what you mean about the trigger. i made one from plastic once and even though it worked and felt great, it looked awful so off it came.

Have you seen my custom hand built garden furniture leg stock for the S200? :twisted: I have handled and shot numerous S200s in my time but obviously none of them fit me as well as this one. I remember lying prone on the floor and getting my daughter to measure the key points before I drew it all up and started hacking the wood.

Started like this ... The 'Leg'
Image


And ended up like this ... The 'Legend'
Image
“It's the Indian, not the arrow"

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Paddy1000111
Posts: 7
Joined: Tue Jun 16, 2020 12:54 pm

Re: S200 power tuning and adjustment

Thu Jul 30, 2020 8:54 pm

That looks awesome! I've not done too much with my stock. I've put an adjustable cheek piece in, adjustable butt plate and then I've just rounded the stock off a little, not enough to change it's looks but enough to make it feel a bit nicer in use. I've used a router bit to round the fore-end off slightly as I never found the square edges nice to hold, I've taken the bottom of the pistol grip and made it look a little nicer and then bought in the wood leading into the trigger as I found that my finger was always in an odd position because of the shape.

Started off in the standard finish with a few bumps and lumps:
Image

and this is how it looks about 2 coats before the final coat:

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Hopefully when it's all back together and on it's final coat it should be a beauty!

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Raj
Posts: 1965
Joined: Sun Feb 15, 2015 9:36 pm
Location: Rugby

Re: S200 power tuning and adjustment

Fri Jul 31, 2020 6:15 am

That is fabulous! Takes a brave man to start cutting into an intact stock like that and the results are brilliant. You also had some good grain on the wood which has been enhanced by the new contours. The main reason i built the custom stock was because the butt end, the comb area and the pistol grip area of my two piece Mk.2 stock all felt a tad wrong. The corners on the fore end needed breaking but I also found the size a touch smaller than i needed ... but I actually liked the flat bottom. I compromised by making the fore end cross section a touch heftier, retained the flat where it comes into contact with a bag or my palm and putting a rounded chamfer on the corners. I also inserted a groove for my finger tips where they wrap round the fore end. The top of the fore end as you can see naturally floats the barrel.

The challenge of getting some pinch between the two sides and the air cylinder was overcome by sourcing a brass insert with outside and inside threads. The outer threads go into the wood. The inner threads house a grub screw with a nylon plug on its front end which prevents marking the cylinder! i found it on a website somewhere, wrote off to them for samples and they sent me two in the post ... FOC!

Image

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Where is your location? We must meet up for an S200 gloat when yours is finished! I am in Rugby, Warwicks.
“It's the Indian, not the arrow"

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Paddy1000111
Posts: 7
Joined: Tue Jun 16, 2020 12:54 pm

Re: S200 power tuning and adjustment

Fri Jul 31, 2020 6:56 pm

Good idea with the screw! You were lucky to nab those for free! I've been re-assembling today with the Crono on the list for tomorrow. I've got a small issue with the barrel and cylinder alignment though. It seems that when it's on the bi-pod the cylinder flexes up causing the barrel and cylinder to be less than 0.6mm apart at the end as the cylinder is longer than before with the reg and the filling adaptor. I made some shims up to 0.14mm as that's what the gap was between the cylinder and the breach block was and it's made no difference. It's not touching but it's closer than I would like.

Shims:
Image

Apart from that it looks pretty good now!
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